This invention relates to waveguide coupling devices for high frequency waveguides, such as used for microwaves, and particularly to a waveguide coupling which rotates the plane of polarization of the waves transmitted through the waveguide.
Many different arrangements have been used to rotate the plane of polarization of a transmitted high frequency wave. For example, couplings have been used which have a stack of similar elements, each with a slot corresponding to the waveguide cross section which are successively stepped to effect rotation. It has been necessary to use substantial gearing and interconnecting mechanisms in such an arrangement for rotating the plane of polarization in constant even increments through the successive slots in these devices. The coupling is operated by an external motor or other actuating means which is bulky, and the devices are generally limited to noncontinuous rotations.
Another type of device which is of interest with respect to rotation of the plane of polarization is disclosed in the patent to Moore U.S. Pat. No. 3,708,767 which shows a rotary adjusting means for polarization orientation. The Heeren U.S. Pat. No. 3,622,921 also discloses a polarization rotator which uses a dielectric disc powered by an external motor. The patent to Hudspeth 4,060,781 uses a stepping motor system for adjusting rotational angle of a quarter wave plate.
However, none of these devices permits the precise rotation of the plane of polarization in ninety degree increments, nor do they also provide for both continuous or incremental rotation. There is also a need for a simply constructed polarization rotation switch that will not be bulky and too costly.